Since iOS4 became available, I've been hearing reports of people experiencing terrible performance on their iPhone 3G shortly after upgrading to the latest OS. Problems range from hanging apps and slow swiping to freezing iPhones.
As of this writing, Apple has not officially acknowledged that there's an issue other than advising users to do a restore and then manually sync everything back. Basically, starting as if your iPhone is brand new. Apple is also stating that
"Not all features are compatible with all devices. For example, multitasking is available only with iPhone 4 and iPhone 3GS."
This weekend I heard multiple reports of people bringing their iPhone 3G running iOS4 to the Apple Store and in some cases, having Apple exchange it for an iPhone running 3.1.3. According to reports, you still have to be within the one year warranty of the original purchase date of the iPhone 3G in order to be considered for the exchange.
I should mention that the above is not an officially sanctioned offering from Apple, so there's no guarantee that you can exchange your iPhone 3G.
If you're wondering how your iPhone 3G might work after you upgrade it to iOS4, check out the video below (thanks to appadvice)
To be fair, I think it's OK that Apple has offered up the option to upgrade your iPhone 3G to the latest OS. The only issue I have is that Apple isn't coming clean with all of the issues that you might experience. If the company mentioned other issues, not just that multitasking doesn't work, then it would be ok.
Of course, now that there have been widespread complaints from folks who have been dealing with poor performing iPhone 3G devices after upgrading, Apple should offer the ability to restore to an earlier OS again.
Did you upgrade your iPhone 3G? How has your experience been?
UPDATE:Roger sent word that since installing iOS4 on his iPod Touch 3rd Generation, the battery loses power at an alarming rate even when switched off. There's a discussion thread dedicated to the topic, which as of this writing is 42 pages deep.
UPDATE2:rory sent word that if you turn off "spotlight search" in settings, the iPhone 3G comes back to life. Comment below if that fixed the issue for you.